Log carriage



K. E. EVRELL LOG CARRIAGE June 13, 1939.

Filed Feb. 2, 1937 5 Sheets-Sheet 1 KALEB EV/e541- .Ai-Zwroeya.

June 13, 11939. K; E. EVRELL 2 LOG CARRIAGE Filed Feb. 2, 1957 3 SheetsSheet 2 6 1 J Av G 923 a I m cl mwcuc v HWHeyg,

June 13, 1939. K. E. EVRELL LOG CARRIAGE Filed Feb. 2, 1937 3 Sheets-Sheet 5 we Emu Kaleb 5F. fvram N MW M W itarnez a Patented June 13, 1939 UNITED STATES LOG CARRIAGE.

Kaleb Emil Evrell, Eskilstuna, Sweden, assignor to Aktiebolaget Bolinder-Munktell, a corporation of Sweden Application February 2, 1937, Serial No. 123,709 In Sweden February 10, 1936 18 Claims.

In saw-mills there are used log carriages which carry the logs when the same are moved towards and through the saw frame and which are provided with devices for holding the logs usually made in the form of claws or the like gripping elements. Modern log carriages are further provided with adjusting devices for the logs such as means for adjusting the logs in different lateral positions and means for turning the logs about their own axes.

For moving the log carriage towards and from the saw frame two warping chains are used which in most cases are disposed below the log carriage and to which the carriage is alternatively secured. It is the primary object of the invention to provide means for generating the pressure of the medium working on the servo motor by means of the movement of the warping chains.

Further, the arrangement of the different parts according to the invention is such that at least one of the warping chains is always positively connected to a part carried by the log carriage.

A still further object of the invention is so to arrange the different transmission members that the motion of the log carriage and the driving power for the pump or compressor delivering the medium under pressure for the servo motor can be derived from the warping chains at the same time. The transmission preferably comprises a differential gear the primary parts of which are coupled to the warping chains and the secondary parts of which are connected to the pressure pump, compressor, or the like.

For a better understanding of the nature of the invention together with further objects and advantageous details and combinations of parts, and the manner in which it is carried into effect, reference may be had to the accompanying drawings forming a part of this specification and the folowing description thereof.

In the drawings:

Fig. 1 shows an end elevation of a log carriage constructed in accordance with this invention, the right-hand lower portion being shown in section taken on the line I--I of Figure 261;

Fig. 2 is a side elevation of the carriage shown in Fig. 1;

Figure 2a. is a section through the lower portion of the carriage, taken on the line II-II of Figure 1;

Fig. 3 is a top view of the carriage shown in Fig. l;

l is a horizontal central section on a larger scale Of a transmission gear by means of which the pump or the like is driven from the warping chains;

Fig. 5 is a side elevation, partly in section and on a larger scale, of the transmission diagrammatically illustrated in Figs. 1 to 3; 5

Fig. 6 is a horizontal central section taken on line X[IXII of Fig. 5.

Referring to Figs. 1 to 3, reference numerals I and 2 designate the warping chains by means of which the log carriage is moved and which are travelling in opposite directions, as indicated by the arrows I and 2' respectively. The chains l and 2 are in permanent mesh with chain wheels 3 and 4, respectively, mounted in the carriage. Reference numerals 5 and 6 designate brake pedals by which the chain wheels 3 and 4 respectively may be locked. The pedal 6 is pivoted to a cranked lever mounted at 4|. The arm 42 of the lever is connected to a brake band 43 secured at 44 and surrounding a brake drum 45 made in one piece with the chain wheel 4. By means of a helical spring 46, the pedal 6 is normally kept in the upper position. When the pedal is pressed down, the lever will pivot about 4| in a clockwise direction and thereby press the band 43 against the drum 45 so as to brake the chain wheel 4. In a similar manner, the brake pedal 5 is arranged to act on the chain wheel 3. If the chain wheel 3 is locked the log carriage follows the chain I meshing with the said wheel in the direction of the arrow I towards the saw frame. If the chain wheel 4 is locked and the chain .wheel 3 released the carriage will move in the opposite direction. For the purpose of holding a log on the carriage there 3 are provided gripping irons l and 8 pivotally secured to a bearing member 9. By means of a wheel H] the gripping device 1-9 may be turned about an axis parallel to the direction of movement of the carriage, and by means of a lever H the gripping device may be turned about a shaft l2 so that it will be possible to lower the gripping irons down to the log carrier I3, in order that they shall not hinder a log from being rolled upon the carriage. The gripping device together with the log carrier I3 may be moved upon the shaft l2 in the axial direction thereof, the shaft [2 being formed, along a portion of its length, into a rack adapted to mesh with a pinion 15 connected to a hand wheel l4.

In the embodiment illustrated, the power necessary for supplying the servo motor with medium under pressure is derived from the warpingchains by means of a transmission device in the form of a toothed wheel gear the primary or driving wheels of which are the chain wheels 3 and 4. By means of the transmission gear which is enclosed by a casing I1, a pump or compressor I9 is driven so as to generate a hydraulic or pneumatic pressure. In the present embodiment a hydraulic servo motor I8 is arranged to control the gripping device 19. The casing of the servo motor is secured to the bearing member 9 of the gripping irons and follows the lateral and vertical movements of the said bearing member.

Oil is preferably used as liquid under pressure. From a container 20 such oil is supplied through a pipe 2| to the pump I9 which delivers the oil under pressure through a pipe 22 and a flexible conduit 23 to a valve chest 24 preferably made integral with the casing of the servo motor. By means of a return pipe 25 the oil is led back from the servo motor to the container 20. Disposed in the pressure conduit 23 is a safety valve 26 which normally serves as an overflow valve in order to maintain a constant pressure of the oil supplied to the servo motor or to prevent an undue rise of this pressure. This valve through which oil in excess flows over into the oil container 20 may also be entirely opened by means of a lever 21. The lever 21 as well as an eccentric 28 are rigidly mounted on a shaft 29. When the log carrage upon moving towards the saw frame approaches its end position, the lever 21 abuts against a stop (not shown in the drawings) and thus turns the shaft 29 and the eccentric 28 which by means of a rod 30 acts upon a stem 3I connected to the cone of the safety valve 26, thereby entirely opening the said valve. This results in that the supply of oil to the servo motor ceases so that the gripping irons will be released from the log.

As indicated above, the transmission means for the pump I9 is driven by the chain wheels 3 and 4 which rotate in opposite directions when the log carriage is at rest. If one of these chain wheels is braked, the other one will rotate at increased speed, since the carriage is then moving in the same direction as thewarping chain meshing with the braked Wheel. The relative velocity of the warping chain of the freely rotating chain wheel will be equal to the sum of the velocities of both warping chains, and the appertaining chain wheel .will obtain a corresponding maximum speed. The speeds of the chain wheels may thus bevaried between nought and the said maximum speed. .No matter how. the speeds are varied it will be evident that the sum of the speeds of the chain wheels will be constant and equal to the said maximum value.

In the two embodiments of the transmission shown in Fig. 4 and Figs. 5. 6 respectively, the motion of the chain wheels is transformed into a rotary movement having a certain direction at a constant speed. A condition for the transmission is that. when the carriage is at a standstill, the resistance exerted by the driven pump be equally distributed among both chain wheels 3 and 4. If the resistance would act upon one chain wheel with a greater force than on the other one, this would result in an undesired tendency to move the log carriage in the same direction as that warping chain the chain wheel of which is acted upon by the greater resistance.

In the embodiment shown in Fig. 4 the transmission device consists of a reversing gear for reversing the direction of rotation of the chain wheels. The reversing gear comprises a bevel wheel I32 rigidly connected to the chain wheel 3, bevel wheels I34 rotatably mounted on pins 99 secured to the casing I1, and a bevel wheel I35. The Wheels I34 mesh with the wheels I32 and I35 so that the wheel I35 will rotate at the same speed as, but in opposite direction to that of the chain wheel 3. The bevel wheel I31 rigidly connected with the wheel I35 will thus rotate in the same direction as the bevel wheel I36 which is rigidly connected with the chain wheel 4. The wheels I36 and I31 have equal diameters and are arranged as sun wheels appertaining to a diflerential gear the planetary wheels of which are designated at I39.

In the same manner as described above with respect to the chain wheels 3 and 4, the sun wheels I36 and I31 will rotate at speeds varying between nought and a maximum value such that the sum of their speeds will be equal to the said maximum value. The planetary wheels I39 are loosely mounted on pins I33 rigidly connected with a planetary wheel carrier I38 which is loosely mounted on a central shaft I43. The planetary wheel carrier and the gear wheel I40 secured thereon will rotate about the shaft I43 at a speed equal to the mean value of the speeds of the sun wheels I36 and I31, that is at a speed equal to half the maximum speed of the sun wheels. The gear wheel I40 will thus always rotate in one and the -same direction and at a speed proportional to the sum of the velocities of the warping chains. The gear wheel I40 meshes with a gear wheel I44 mounted on a shaft I45 which drives the liquid pump I9. The pump which is in the form of a gear driven pump is thus permanently driven at constant speed so that always a satisfactory liquid pressure will be maintained.

The gear wheels I35 and I31 secured to each other are mounted on a central portion I M of the casing I1, the portion I4I being secured against rotation relatively to the stationary shaft I43 by means of a key I42. It will be seen that in the described transmission device the resistance exerted by the driven pump will be equally distributed among the chain wheels 3 and 4 so that the turning moments acting thereupon will be equal to each other.

In the embodiment shown in Fig. 4 the axis of rotation of the differential gear is in alignment with the axes of rotation of the chain wheels 3 and 4. Since the differential gear is disposed between the said wheels, the distance between the same will be somewhat greater than is usual in existing standard log carriages.

Figs. 5 and 6 illustrate a preferred form of a transmission device similar to that described above but arranged in such a manner that the distance between the chainwheels 3 and 4 can be reduced so that the transmission can be applied to existing log carriages without rebuilding.

Rigidly connected with the chain wheels 3 and 4 are bevel wheels I46 and I41 respectively meshing with bevel wheels I48 and I49 respectively, which are mounted on shafts I48 and M9 respectively arranged concentrically and rotatably relatively to each other, the shaft I48 being in the form of a hollow shaft surrounding the shaft I49. The shafts I48 and I49 carry at their outer ends bevel wheels I50 and I5I respectively serving as sun wheels in a differential'gear the planetary wheels I52 of which are loosely mounted on pins I53 secured to a carrier I54 which is rotatably mounted on the shaft I49.

In the manner described in connection with the embodiment shown in Fig. 4, the bevel wheels I48 and M9 will rotate at speeds varying between nought and a maximum value such that the sum of their speeds will always be equal to the said maximum value. The wheels I48 and I49 as well as the sun wheels I50 and I! will always rotate in the same direction. The differences in their speeds will be equalized by the differential gear so that the planetary wheel carrier will rotate at a speed equal to the mean value of the speeds of the sun wheels. Secured to the carrier IE4 is a gear wheel I56 which by means of a gear wheel M4 transmits the rotation of the carrier to a shaft Hi5 driving a liquid pump, compressor or the like Hi.

The embodiment shown in Figs. 5 and 6 is assumed to be applied to the log carriage illustrated in Figs. 1 to 3. In this instance, the axis of rotation of the differential gear is disposed at a right angle with respect to the axis of rotation of the chain wheels 3 and t. If required for practical reasons, the named axes of rotation may obviously be arranged at any other angle with respect to each other.

Itwill be obvious that the pump [9 may be arranged to supply pressure medium also to other servo motors than the servo motor operating the gripping device for the log. It may, for instance, be arranged to supply pressure medium to a servo motor adapted to effect a lateral movement of the gripping device, or to a servo motor devised for turning the log about its own axis.

I do not desire to be limited to the exact construction and arrangement shown and described, as changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

What I claim is:

1. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, and means for driving said impeller by said warping chains.

2. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, a pressure conduit for supplying said pressure medium to said servo motor, a return conduit for returning said medium to the inlet of said impeller, and means for driving said impeller by said Warping chains.

3. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, a pressure conduit for supplying said pressure medium to said servo motor, a return conduit for returning said medium to the inlet of said impeller, a safety valve disposed in said pressure conduit and adapted to maintain constant the pressure of said pressure medium supplied to said servo motor, and means for driving said impeller by said warping chains.

4. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said 10g carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, a pressure conduit for supplying said pressure medium to said servo motor, a return conduit for returning said medium to the inlet of said impeller, an overflow valve disposed in said pressure conduit and adapted to maintain constant the pressure of said pressure medium supplied to said servo motor, a container for said medium disposed in said return conduit, means for connecting said overflow valve to said container, and means for driving said impeller by said warping chains.

5. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, a pressure conduit for supplying said pressure medium to said servo motor, a return conduit for returning said medium to the inlet of said impeller, a safety valve disposed in said pressure conduit and adapted to maintain constant the pressure of said pressure medium supplied to said servo motor, actuating means for controlling said safety valve, said actuating means being adapted automatically to open said safety valve when said log carriage upon its movement arrives at a predetermined point, and means for driving said impeller by said warping chains.

'6. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an im peller for delivering pressure medium, a pressure conduit for supplying said pressure medium to said servo motor, a return conduit for returning said medium to the inlet of said impeller, a safety valve disposed in said pressure conduit and adapted to maintain constant the pressure of said pressure medium supplied to said servo motor, an actuating member for controlling said safety valve, stopping means disposed in the path of said carriage and adapted to open said safety valve when said actuating member comes into contact with said stopping means, and means for driving said impeller by said warping chains.

'7. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel andasecondchain wheel adapted to mesh with said warping chains respectively,means forbraking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, and means for driving said impeller by either of said chain wheels.

8. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, and means for driving said impeller by both of said chain wheels simultaneously.

9. In a log carriage arrangement for saw mills,

- two warping chains adapted to be driven in onposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction. a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device. an impeller for delivering pressure medium. means for supplying said pressure medium to said servo motor, and a differential power transmission gear comprising a primary part and a secondary part. said primry part being connected to said chain wheels. and said secondary part being I connected to said impeller.

10. In a log carriage arrangement for saw m lls, two warping chains adapted to be driven in onposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively. means for braking either of said chain wheels whereby to move said 10;! carriage in either direction, a gripping device for holding a log during the sawing operation. a servo motor for actuating said gripp ng device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, and a differential power transmission gear for transmitting power from said chain wheels to said impeller, said transmission gear being devised to transmit to said impeller a constant amount of power irrespective of the number of said chain wheels being driven by said warping chains.

11. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising two primary gear wheels and at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel and for transmitting the movement thereof to said impeller, and means for driving both of said primary gear wheels by said chain wheels in the same direction of rotation.

12. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising two primary gear wheels and at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel and for transmitting the movement thereof to said impeller, and means for driving both of said primary gear wheels by said chain wheels in the same direction of rotation, said transmission gear being devised to transmit upon said chain wheels equal amounts of the resistance exerted by said impeller.

13. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delvering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising two primary gear wheels and at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel and for transmitting the movement thereof to said impeller, and means for driving both of said primary gear wheels by said chain wheels in the same direction of rotation, the axes of rotation of said primary gear wheels forming an angle with the axis of rotation of said chain wheels.

14. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising a first primary gear wheel secured on a first shaft and a second primary gear wheel secured on a second shaft, the axes of rotation of said primary gear wheels forming an angle with the axes of rotation of said chain wheels, at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel and for trans mitting the movement thereof to said impeller, said shafts being disposed coaxial and with one of them surrounding the other one, a first bevel wheel mounted on said first shaft, a second bevel wheel connected to said first chain wheel and adapted to mesh with said first bevel wheel, a third bevel wheel mounted on said second shaft, and a fourth bevel wheel connected to said second chain wheel and adapted to mesh with said third bevel wheel.

15. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising two primary gear wheels and at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel and for transmitting the movement thereof to said impeller, and means for driving both of said primary gear wheels by said chain wheels in the same direction of rotation, the transmission ratio between said first bevel wheel and said second bevel wheel being equal to the transmission ratio between said third bevel wheel and said fourth bevel wheel.

16. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising two primary gear wheels and at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel and for transmitting the movement thereof to said impeller, and means for driving both of said primary gear wheels by said chain wheels in the same direction of rotation, the axes of rotation of said primary gear wheels being parallel to the axes of rotation of said chain wheels.

17. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising a first primary gear wheel, a reversing gear interposed between said first chain wheel and said first primary gear wheel, a second primary gear wheel connected to said second chain wheel, at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel, and means for transmitting the movement of said wheel carrier to said impeller.

18. In a log carriage arrangement for saw mills, two warping chains adapted to be driven in opposite directions from a source of power outside the log carriage, a first chain wheel and a second chain wheel adapted to mesh with said warping chains respectively, means for braking either of said chain wheels whereby to move said log carriage in either direction, a gripping device for holding a log during the sawing operation, a servo motor for actuating said gripping device, an impeller for delivering pressure medium, means for supplying said pressure medium to said servo motor, a differential power transmission gear comprising two primary gear wheels and at least one secondary gear wheel, a wheel carrier for carrying said secondary gear wheel, a gear wheel secured to said wheel carrier and adapted to transmit the movement thereof to said impeller, and means for driving both of said primary gear wheels by said chain wheels in the same direction of rotation.

KALEB EMl'L EVRELL. 

